STOCKHOLM, May 8 (Reuters) - Swedish builder Skanska reported a smaller-than-expected rise in operating earnings for the first quarter on Wednesday as profits in its bread-and-butter construction business recorded a year-on-year fall.

The Nordic region's biggest construction group said operating earnings rose to 497 million crowns ($45.6 million) from a year-ago 394 million, lagging the 873 million seen in a LSEG compilation of analysts' forecasts.

The company, which is also a significant player in the U.S. construction market, said construction results were solid in the Nordic and U.S. markets but that its European business had been hit by costs related to a ten-year-old project in Britain. ($1 = 10.8929 Swedish crowns) (Reporting by Niklas Pollard, editing by Anna Ringstrom)